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                            <div style="color:gray; word-break: break-all; font-size:12px;">原英文版地址: <a href="https://www.elastic.co/guide/en/elasticsearch/reference/7.7/analysis-flatten-graph-tokenfilter.html" rel="nofollow" target="_blank">https://www.elastic.co/guide/en/elasticsearch/reference/7.7/analysis-flatten-graph-tokenfilter.html</a>, 原文档版权归 www.elastic.co 所有<br/>本地英文版地址: <a href="../en/analysis-flatten-graph-tokenfilter.html" rel="nofollow" target="_blank">../en/analysis-flatten-graph-tokenfilter.html</a></div>
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<span class="breadcrumb-node">Flatten graph token filter</span>
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<div class="titlepage"><div><div>
<h2 class="title">
<a id="analysis-flatten-graph-tokenfilter"></a>Flatten graph token filter<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/flatten-graph-tokenfilter.asciidoc">edit</a>
</h2>
</div></div></div>

<p>Flattens a <a class="xref" href="token-graphs.html" title="Token graphs">token graph</a> produced by a graph token filter, such
as <a class="xref" href="analysis-synonym-graph-tokenfilter.html" title="Synonym graph token filter"><code class="literal">synonym_graph</code></a> or
<a class="xref" href="analysis-word-delimiter-graph-tokenfilter.html" title="Word delimiter graph token filter"><code class="literal">word_delimiter_graph</code></a>.</p>
<p>Flattening a token graph containing
<a class="xref" href="token-graphs.html#token-graphs-multi-position-tokens" title="Multi-position tokens">multi-position tokens</a> makes the graph
suitable for <a class="xref" href="analysis-index-search-time.html" title="Index and search analysis">indexing</a>. Otherwise, indexing does
not support token graphs containing multi-position tokens.</p>
<div class="warning admon">
<div class="icon"></div>
<div class="admon_content">
<p>Flattening graphs is a lossy process.</p>
<p>If possible, avoid using the <code class="literal">flatten_graph</code> filter. Instead, use graph token
filters in <a class="xref" href="analysis-index-search-time.html" title="Index and search analysis">search analyzers</a> only. This eliminates
the need for the <code class="literal">flatten_graph</code> filter.</p>
</div>
</div>
<p>The <code class="literal">flatten_graph</code> filter uses Lucene’s
<a href="https://lucene.apache.org/core/8_5_1/analyzers-common/org/apache/lucene/analysis/core/FlattenGraphFilter.html" class="ulink" target="_top">FlattenGraphFilter</a>.</p>
<div class="section">
<div class="titlepage"><div><div>
<h3 class="title">
<a id="analysis-flatten-graph-tokenfilter-analyze-ex"></a>Example<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/flatten-graph-tokenfilter.asciidoc">edit</a>
</h3>
</div></div></div>
<p>To see how the <code class="literal">flatten_graph</code> filter works, you first need to produce a token
graph containing multi-position tokens.</p>
<p>The following <a class="xref" href="indices-analyze.html" title="Analyze API">analyze API</a> request uses the <code class="literal">synonym_graph</code>
filter to add <code class="literal">dns</code> as a multi-position synonym for <code class="literal">domain name system</code> in the
text <code class="literal">domain name system is fragile</code>:</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">GET /_analyze
{
  "tokenizer": "standard",
  "filter": [
    {
      "type": "synonym_graph",
      "synonyms": [ "dns, domain name system" ]
    }
  ],
  "text": "domain name system is fragile"
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/928.console"></div>
<p>The filter produces the following token graph with <code class="literal">dns</code> as a multi-position
token.</p>
<div class="imageblock text-center">
<div class="content">
<img src="../static/images/analysis/token-graph-dns-synonym-ex.svg" alt="token graph dns synonym ex">
</div>
</div>
<p>Indexing does not support token graphs containing multi-position tokens. To make
this token graph suitable for indexing, it needs to be flattened.</p>
<p>To flatten the token graph, add the <code class="literal">flatten_graph</code> filter after the
<code class="literal">synonym_graph</code> filter in the previous analyze API request.</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">GET /_analyze
{
  "tokenizer": "standard",
  "filter": [
    {
      "type": "synonym_graph",
      "synonyms": [ "dns, domain name system" ]
    },
    "flatten_graph"
  ],
  "text": "domain name system is fragile"
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/929.console"></div>
<p>The filter produces the following flattened token graph, which is suitable for
indexing.</p>
<div class="imageblock text-center">
<div class="content">
<img src="../static/images/analysis/token-graph-dns-invalid-ex.svg" alt="token graph dns invalid ex">
</div>
</div>
</div>

<div class="section">
<div class="titlepage"><div><div>
<h3 class="title">
<a id="analysis-keyword-marker-tokenfilter-analyzer-ex"></a>Add to an analyzer<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/flatten-graph-tokenfilter.asciidoc">edit</a>
</h3>
</div></div></div>
<p>The following <a class="xref" href="indices-create-index.html" title="Create index API">create index API</a> request uses the
<code class="literal">flatten_graph</code> token filter to configure a new
<a class="xref" href="analysis-custom-analyzer.html" title="Create a custom analyzer">custom analyzer</a>.</p>
<p>In this analyzer, a custom <code class="literal">word_delimiter_graph</code> filter produces token graphs
containing catenated, multi-position tokens. The <code class="literal">flatten_graph</code> filter flattens
these token graphs, making them suitable for indexing.</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">PUT /my_index
{
  "settings": {
    "analysis": {
      "analyzer": {
        "my_custom_index_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "my_custom_word_delimiter_graph_filter",
            "flatten_graph"
          ]
        }
      },
      "filter": {
        "my_custom_word_delimiter_graph_filter": {
          "type": "word_delimiter_graph",
          "catenate_all": true
        }
      }
    }
  }
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/930.console"></div>
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